The present disclosure relates generally to turbine exhaust systems, and particularly to turbine exhaust diffusers.
Current gas turbine engines utilize an exhaust frame to support an exterior exhaust housing, or stator casing. The exhaust frame and exterior housing are made from structural steel, which is not capable of withstanding a temperature of turbine exhaust gases. Therefore, diffusers made from a material that is capable of withstanding the temperature of exhaust gases are utilized to shield the exhaust frame and exterior housing from exposure to the temperature of exhaust gases. Furthermore, blowers may be used to provide cool air for additional shielding of the exhaust frame from the temperature of exhaust gases. In conjunction with blowers, seals between the diffuser and the exhaust frame can be used to direct the cool air to appropriate locations and to reduce undesired leakage. Attention to control challenges that result from differential thermal expansion of the frame and the diffuser can yield complex and costly design and operational solutions. Accordingly, there is a need in the art for a turbine exhaust arrangement that overcomes these drawbacks.